expect-puppeteer
Advanced tools
The expect-puppeteer package is a set of utility functions that integrate Jest's expect assertions with Puppeteer's browser automation capabilities. It allows for more readable and expressive tests when working with Puppeteer.
toMatch
This feature allows you to assert that a specific text appears on the page. It simplifies the process of checking for text content within the page.
await expect(page).toMatch('text to match');toClick
This feature allows you to simulate a click event on a specified element. It is useful for testing interactions with buttons, links, and other clickable elements.
await expect(page).toClick('button#submit');toFill
This feature allows you to fill out form fields with specified values. It is useful for testing form submissions and input handling.
await expect(page).toFill('input[name="username"]', 'myUsername');toSelect
This feature allows you to select an option from a dropdown menu. It is useful for testing interactions with select elements.
await expect(page).toSelect('select#dropdown', 'optionValue');toUploadFile
This feature allows you to simulate file uploads by specifying the file path. It is useful for testing file input elements.
await expect(page).toUploadFile('input[type="file"]', 'path/to/file.txt');jest-puppeteer provides a set of utilities to run Puppeteer with Jest. It offers a more comprehensive setup for integrating Puppeteer with Jest, including custom environment setup and teardown, but it does not include the same level of syntactic sugar for assertions as expect-puppeteer.
puppeteer-testing-library is a set of utilities for using the Testing Library queries with Puppeteer. It focuses on providing a more user-centric approach to querying and interacting with elements, similar to the philosophy of the Testing Library family of packages.
puppeteer-extra is a modular plugin framework for Puppeteer. It allows you to extend Puppeteer's functionality with plugins, such as stealth mode and adblocker. While it does not provide assertion utilities, it enhances Puppeteer's capabilities in other ways.
Assertion library for Puppeteer.
npm install expect-puppeteer
Without Jest:
import expect from 'expect-puppeteer'
;(async () => {
const browser = await puppeteer.launch()
const page = await browser.newPage()
await page.goto('https://google.com')
await expect(page).toMatch('google')
await browser.close()
})()
To use with Jest, just modify your configuration:
{
"setupFilesAfterEnv": ["expect-puppeteer"]
}
Writing integration test is very hard, especially when you are testing a Single Page Applications. Data are loaded asynchronously and it is difficult to know exactly when an element will be displayed in the page.
Puppeteer API is great, but it is low level and not designed for integration testing.
This API is designed for integration testing:
Example
// Does not work if button is not in page
await page.click('button')
// Will try while 500ms to click on "button"
await page.toClick('button')
// Will match a button with a "My button" text inside
await page.toClick('button', { text: 'My button' })
Expect an element to be in the page or element, then click on it.
instance <Page|ElementHandle> Contextselector <string> A selector to click onoptions <Object> Optional parameters
button <"left"|"right"|"middle"> Defaults to left.clickCount <number> defaults to 1. See UIEvent.detail.delay <number> Time to wait between mousedown and mouseup in milliseconds. Defaults to 0.text <string|RegExp> A text or a RegExp to match in element textContent.await expect(page).toClick('button', { text: 'Home' })
Expect block function to trigger a dialog and returns it.
const dialog = await expect(page).toDisplayDialog(async () => {
await expect(page).toClick('button', { text: 'Show dialog' })
})
Expect a control to be in the page or element, then fill it with text.
instance <Page|ElementHandle> Contextselector <string> A selector to match fieldvalue <string> Value to filloptions <Object> Optional parameters
delay <number> delay to pass to the puppeteer element.type APIawait expect(page).toFill('input[name="firstName"]', 'James')
Expect a form to be in the page or element, then fill its controls.
instance <Page|ElementHandle> Contextselector <string> A selector to match formvalues <Object> Values to filloptions <Object> Optional parameters
delay <number> delay to pass to the puppeteer element.type APIawait expect(page).toFillForm('form[name="myForm"]', {
firstName: 'James',
lastName: 'Bond',
})
Expect a text or a string RegExp to be present in the page or element.
instance <Page|ElementHandle> Contextmatcher <string|RegExp> A text or a RegExp to match in pageoptions <Object> Optional parameters
polling <string|number> An interval at which the pageFunction is executed, defaults to raf. If polling is a number, then it is treated as an interval in milliseconds at which the function would be executed. If polling is a string, then it can be one of the following values:
raf - to constantly execute pageFunction in requestAnimationFrame callback. This is the tightest polling mode which is suitable to observe styling changes.mutation - to execute pageFunction on every DOM mutation.timeout <number> maximum time to wait for in milliseconds. Defaults to 30000 (30 seconds). Pass 0 to disable timeout. The default value can be changed by using the page.setDefaultTimeout(timeout) method.// Matching using text
await expect(page).toMatch('Lorem ipsum')
// Matching using RegExp
await expect(page).toMatch(/lo.*/)
Expect an element be present in the page or element.
instance <Page|ElementHandle> Contextselector <string> A selector to match elementoptions <Object> Optional parameters
polling <string|number> An interval at which the pageFunction is executed, defaults to raf. If polling is a number, then it is treated as an interval in milliseconds at which the function would be executed. If polling is a string, then it can be one of the following values:
raf - to constantly execute pageFunction in requestAnimationFrame callback. This is the tightest polling mode which is suitable to observe styling changes.mutation - to execute pageFunction on every DOM mutation.timeout <number> maximum time to wait for in milliseconds. Defaults to 30000 (30 seconds). Pass 0 to disable timeout. The default value can be changed by using the page.setDefaultTimeout(timeout) method.text <string|RegExp> A text or a RegExp to match in element textContent.visible <boolean> wait for element to be present in DOM and to be visible, i.e. to not have display: none or visibility: hidden CSS properties. Defaults to false.// Select a row containing a text
const row = await expect(page).toMatchElement('tr', { text: 'My row' })
// Click on the third column link
await expect(row).toClick('td:nth-child(2) a')
Expect a select control to be present in the page or element, then select the specified option.
instance <Page|ElementHandle> Contextselector <string> A selector to match select elementvalueOrText <string> Value or text matching optionawait expect(page).toSelect('select[name="choices"]', 'Choice 1')
Expect a input file control to be present in the page or element, then fill it with a local file.
instance <Page|ElementHandle> Contextselector <string> A selector to match input elementfilePath <string> A file pathimport path from 'path'
await expect(page).toUploadFile(
'input[type="file"]',
path.join(__dirname, 'file.txt'),
)
To configure default options like timeout, expect-puppeteer exposes two methods: getDefaultOptions and setDefaultOptions. You can find available options in Puppeteer page.waitForFunction documentation. Default options are set to: { timeout: 500 }.
import { setDefaultOptions } from 'expect-puppeteer'
setDefaultOptions({ timeout: 1000 })
MIT
FAQs
Assertion toolkit for Puppeteer.
We found that expect-puppeteer demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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